Taiwanese company ProLogium has announced the start of mass production of fully solid-state battery cells, in a move it says takes the technology from the prototype stage to actual manufacturing. The company’s facility in Taoyuan is producing its first large-format pouch cells, with an initial capacity of 0.5 gigawatt-hours.
ProLogium has investment backing from Mercedes-Benz and other industrial entities, but current production remains limited compared with conventional electric-vehicle battery plants. The company estimates that the facility’s initial capacity is enough for approximately 6,000 battery packs, assuming each pack has a capacity of 80 kilowatt-hours.
Energy-Density Figures and Cell Testing
The new cell is called the Generation 3.5 Large-Format Lithium Ceramic Battery, and it has a capacity of 185.4 ampere-hours. According to tests conducted by TÜV in Germany, the cell recorded a gravimetric energy density of 381 watt-hours per kilogram and a volumetric energy density of 903 watt-hours per liter.
According to the source material, these figures compare with nickel-manganese-cobalt cells widely used in electric vehicles, which typically reach approximately 300 watt-hours per kilogram at the cell level. Lithium iron phosphate cells, which are less expensive, generally have a gravimetric density of between 150 and 200 watt-hours per kilogram.
UL Solutions also tested a large-format ProLogium cell according to China’s GB/T 43568-2026 methodology, which aims to distinguish fully solid-state cells from cells that still use some liquid electrolyte. After the cell was kept in a vacuum for six hours at a constant temperature of 120 degrees Celsius, its weight loss was less than 0.05%, compared with a maximum limit of 0.5% for the product to qualify as a fully solid-state cell.
What Changes in Practice?
The Gen 3.5 cell uses a composite solid electrolyte and a ceramic separator, along with a special terminal-frame structure that the company says helps isolate potential metal protrusions and provide sealing and insulation. ProLogium claims that its Lithium Ceramic Battery technology can charge from 5% to 80% in less than ten minutes, while the previous Gen 3 generation recorded a time of eight and a half minutes, according to the company’s claim.
The company also says that the Gen 3 cell did not catch fire when exposed to a bullet impact or to overcharging equivalent to twice the nominal voltage. These safety claims remain tied to the specific tests and conditions conducted by the company and do not automatically establish the same performance in every pack or vehicle.
Expansion Beyond Taiwan
ProLogium plans to double production at its Taiwan facility by 2030. In France, the company is working on a second facility in Dunkirk with an initial annual capacity of 4 gigawatt-hours and a designed maximum capacity of 44 gigawatt-hours. The French plant is expected to begin operations in 2028, with production increasing gradually through 2030.
The company says that the fourth generation of its cells is under development, featuring a fully inorganic, highly fluid electrolyte system to improve charging speed and performance at low temperatures. It also says that Gen 3.5 production lines will require only 10% of their equipment to be modified to transition to Gen 4. However, the most important fact at present is that mass production has begun at a relatively small capacity; therefore, the step does not yet demonstrate the technology’s ability to compete with large-scale lithium-ion battery production or achieve comparable costs.